The short range communication system known as DSRC (Dedicated Short Range Communication) is known. DSRC is a wireless communication system with a radio wave range from a few meters to several tens of meters, and is used in ETC (Electronic Toll Collection Systems), and ITS (Intelligent Transport Systems). ETC is a system in which communications take place between antennae installed on gates and on-board equipment mounted in vehicles and charges are paid automatically when vehicles pass charge points on highways and so forth. When ETC is adopted, there is no need to stop at the charge points and hence the time required for vehicles to pass gates is dramatically reduced. Such a system therefore enables traffic congestion in the vicinity of the charge points to be alleviated and exhaust gases to be reduced.
Further, ITS is a traffic system which fuses a system enabling greater vehicle intelligence such as car navigation systems (referred to as ‘Car Navigation System’ hereinafter) with a system enabling superior roadway intelligence such as area traffic control systems. For example, Car Navigation System include systems permitting a hookup with a VICS (Vehicle Information and Communication System). When ITS is used in such a case, general route information gathered by the police and highway information which is collected by the Tokyo Expressway Public Corporation and the Japan Highway Public Corporation is edited and transmitted by a VICS center. Then, when this information is received by a Car Navigation System, a route such as one that enables traffic congestion to be avoided can be sought and displayed on a monitor.
Further, where DSRC is concerned, information is transmitted in this way from wireless communication equipment which is provided at the side of the roadway and in parking facilities and so forth. A DSRC antenna enabling radio waves transmitted from the wireless communication equipment to be received is mounted in a vehicle fitted with a Car Navigation System. DSRC uses the 5.8 GHz band. Also, a GPS antenna is required for a Car Navigation System and a GPS antenna is therefore installed in the vehicle. The GPS uses the 1.5 GHz band. Further, in order to hook up the Car Navigation System with the VICS, a VICS antenna is necessary and hence a VICS antenna is mounted in the vehicle. The VICS (radio wave beacon) uses the 2.5 GHz band.
Thus, because the respective usage frequency bands of the DSRC, GPS and VICS are different, the corresponding antennae must be installed in the vehicle. There is therefore the problem that a plurality of antennae is required, same occupying a broad mount area, and the work involved in mounting a plurality of antennae is complicated.
An object of the present invention is therefore to provide a small composite antenna that is capable of operating in a plurality of different frequency bands.